1. Field of the Invention
The present invention relates to a communication device and a method used in a wireless communication system, and more particularly, to a communication device and method of handling a paging procedure in a wireless communication system.
2. Description of the Prior Art
A user equipment (UE) capable of using an extended discontinuous reception (DRX) parameter cycle transmits an extended DRX parameter to a network, when performing an attach procedure or a tracking area update procedure. The network transmits the same or different extended DRX parameters to the UE, if the network supports the extended DRX parameter and accepts the request from the UE. The UE listens to a paging channel for a paging request by using the same extended DRX parameter transmitted from the network. The extended (e.g., longer) DRX parameter refers that the UE wakes up to listen to the paging channel after an extended duration. Further, the UE attached to a normal service initiates a procedure to establish a packet data network (PDN) connection for an emergency bearer service, and the UE transfers to an idle mode during the procedure because a radio link failure occurs. However, it is unknown which one of the extended DRX parameter and a DRX parameter should be used by the UE, when the UE listens to the paging channel. In addition, it is unknown which one of the extended DRX parameter and the DRX parameter should be used by the network (e.g. Mobility Management Entity (MME)), when the network transmits the paging request to an evolved Node-B (eNB). Thus, the UE and the network may not be synchronous for the paging procedure. As a result, the emergency bearer service (e.g., an emergency call reestablishment procedure) may be delayed.
Thus, how to handle a paging procedure is an important problem to be solved.